With continuing growth of traffic in a mobile communication network, how to enhance throughput of a cellular network has become an important problem. Methods, such as MIMO, beamforming, CoMP, and relay etc., have been employed to enhance throughput of the cellular network and to improve spectrum efficiency. However, these methods increase system complexity. Nowadays, a mobile phone usually has a dual-mode function, which not only can access to the cellular network, but also can use unlicensed frequency spectrum resources, such as Bluetooth network, WiFi network and the like. Thus, wireless network interfaces, such as a WiFi interface, in a mobile phone may be used to utilize the unlicensed frequency spectrum resources, such as WiFi resource, to enhance the throughput of the cellular network.
To this end, a solution of WiFi breakout offload introduces low cost WiFi technology into cellular communications, thereby introducing the unlicensed frequency spectrum resources into the cellular network to increase frequency spectrum resources in the cellular network, so as to alleviate the traffic pressure of a radio access network (RAN) of the cellular network. In this solution, a user equipment operates simultaneously in two wireless modes, i.e., WiFi and 3GPP, and the breakout is configured in the user equipment. The WiFi breakout offload solution comprises two solutions, i.e., seamless offload (as shown in FIG. 1) and seamed offload (as shown in FIG. 2). In the seamless offload solution, a WiFi access network is configured in the core network of operators; while in the seamed offload solution, the WiFi access network is separated from the core network of operators, and thereby the seamed offload solution does not support mobility. Both the seamless offload solution and the seamed offload solution remove traffic load from the whole wireless access network, including its air interface. In addition, a function unit for discovering and selecting the access network should be configured therein, to provide the user equipment with the discovering information and rules with regard to the manners to use the available access network.
However, in this solution, the WiFi access network does not closely coordinate with the 3GPP access network, which triggers a series of problems. For example, the WiFi access network and the 3GPP access network are two peer networks, and an operator needs to maintain and use both networks at the same time, and the cost is thereby increased. Meanwhile, new network nodes (such as the function unit for discovering and selecting the access network and a local proxy and the like) need to be added into the core network of the operator in this solution, and thereby the cost is further increased and the existing core network needs to be modified. In addition, the user equipment or core network determines whether to use traffic offload based on traffic properties and communication fees, and thereby removes traffic load from the whole wireless access network, which causes a decrease in the profit of operators. For example, an operator invests to maintain two networks, however, a great amount of traffic is bypassed to a low cost WiFi access network, and thereby the licensed frequency band is not utilized sufficiently. Meanwhile, this solution skips the whole wireless access network, thus, it cannot obtain information on physical (PHY) layer channels to make a decision for offloading. Therefore, in certain scenarios, this solution cannot provide an optimal solution for the minimum power consumption and maximum throughput of the user equipment, rendering worse flexibility. In addition, a complicated control mechanism is required in handover between two networks, which also affects user experience, and the quality of service QoS cannot be guaranteed when using the WiFi access network.